134 INTRODUCTION 
D. Deceptive Frowers (Fd). 
Parnassia palustris everywhere proves itself to be a Deceptive Fly Flower’. 
Sprengel (‘Entd. Geh.,’ p. 167) confesses that he finds the greatest difficulty in 
interpreting the ‘five sap-producing arrangements, which in alternation with the 
stamens surround the pistil, and of which the structure is quite original and of its kind 
unique.’ We are indebted for a solution of the problem to Hermann Miiller, who 
(‘Alpenblumen,’ p. 112) writes somewhat as follows :—‘ The yellow balls at the end of 
the slender outgrowths from the staminodes resemble drops of fluid so completely 
that we are obliged to convince ourselves by a special test that they are not such, 
but that we have to deal with perfectly dry swellings. Parnassia palustris thus 
appears to hold up to the view of the “stupid flies” some fifty’ drops of nectar 
visible from afar, by which they are strongly attracted. When they approach, how- 
ever, the flowers offer but a very modest 
booty of exposed nectar, in comparison 
to the prospect held out. In fact the “stupid 
flies,” i.e. the Muscidae, are everywhere the 
chief visitors, for astuter insects perhaps 
allow themselves to be deceived once, 
but do not so readily return.’ That this 
interpretation is the correct one, is shown 
by an observation of Hermann Miller, jun., 
who, for a considerable time and from 
no great distance, watched a_hover-fly 
(Eristalis nemorum), which is one of the 
more sagacious Diptera, while it attempted 
to lick these apparent drops, and it was 
Fic. 49. Parnassia palustris, L., a Deceptive Only frightened away by the closer approach 
Fly Flower. A. Flower after removal of three of the observer. 
sepals and four petals, seen exactly from above ; 
(x 5). D. Staminode (highly magnified). 7. Ophrys muscifera also appears to be 
a a Deceptive Fly Flower. Its purple-brown 
velvety labellum, says Hermann Miiller (Kosmos, ii, 1877, p. 335), with its pale-blue 
naked spot, seems exactly as if made to entice, by its colour, flies with a taste 
for decomposing material. Under favourable circumstances a broad median longi- 
tudinal stripe on the labellum, which includes the pale-blue spot, is covered with 
numerous little drops, that Hermann Miiller saw a flesh-fly (Sarcophaga) licking. 
The two shining black tubercles at the base of the labellum, that look like two 
drops of fluid, are regarded by this investigator as pseudo-nectaries, which cannot 
fail to tempt a fly that has approached to try to suck them, thus bringing about 
the first act of cross-pollination. For as the insect stoops down to one of the 
two pseudo-nectaries, it can scarcely fail to touch with its head the projecting 
rostellum, thus causing the adhesion of a pollinium, and when a few minutes later 
1 Cf. the note on Parnassia in Vol. II. 
* In vigorous plants in the Meimersdorf Moss, near Kiel, I saw each of the five staminodes 
ornamented with about twenty-five balls, so that the flowers possessed as many as 125 apparent 
nectar-drops. 
